Real-Time Ethernet Technology Comparison
SERCOS Seminar AtlantaSeptember 16, 2009
Peter Lutz, Managing Director
SERCOS International e.V.
www.infoPLC.net
No. 2(c) SERCOS International 2009
Real-Time Ethernet Competitionwww.infoPLC.net
No. 3(c) SERCOS International 2009
Overview on Real-Time Ethernet Technologies (Selection)
CC Link IE
Drive CliQ
EPA
EtherCAT
EtherNet/IP + CIP Sync
Ethernet Powerlink
IEEE 1588 / PTP
JetSync
Modbus RTPS
Mechatrolink III
PowerDNA
Profinet
RAPIEnet
RTEX
SafetyNET p
SERCOS III
SynqNet
TCnet
Varan
Vnet/IP
Source: http://www.real-time-ethernet.de/
www.infoPLC.net
No. 4(c) SERCOS International 2009
Overview on Real-Time Ethernet Technologies (Selection)
CC Link IE
Drive CliQ
EPA
EtherCAT
EtherNet/IP + CIP Sync
Ethernet Powerlink
IEEE 1588 / PTP
JetSync
Modbus RTPS
Mechatrolink III
PowerDNA
Profinet
RAPIEnet
RTEX
SafetyNET p
SERCOS III
SynqNet
TCnet
Varan
Vnet/IP
Source: http://www.real-time-ethernet.de/
www.infoPLC.net
No. 5(c) SERCOS International 2009
Overview on Real-Time Ethernet Technologies (Selection)
CC Link IE
Drive CliQ
EPA
EtherCAT
EtherNet/IP + CIP Sync
Ethernet Powerlink
IEEE 1588 / PTP
JetSync
Modbus RTPS
Mechatrolink III
PowerDNA
Profinet
RAPIEnet
RTEX
SafetyNET p
SERCOS III
SynqNet
TCnet
Varan
Vnet/IP
Source: http://www.real-time-ethernet.de/
www.infoPLC.net
No. 6(c) SERCOS International 2009
Overview on Real-Time Ethernet Technologies (Selection)
CC Link IE
Drive CliQ
EPA
EtherCAT
EtherNet/IP + CIP Sync
Ethernet Powerlink
IEEE 1588 / PTP
JetSync
Modbus RTPS
Mechatrolink III
PowerDNA
Profinet
RAPIEnet
RTEX
SafetyNET p
SERCOS III
SynqNet
TCnet
Varan
Vnet/IP
Source: http://www.real-time-ethernet.de/
www.infoPLC.net
No. 7(c) SERCOS International 2009
Real-Time Ethernet Protocols:Efficiency / Performance
a) SERCOS III:
b) EtherCAT:
c) Profinet, Ethernet/IP, Ethernet Powerlink:
RT1 RT2 RT3
Tunnelled
Ethernet frames
Separate Ethernet frames
(non-real-time channel)
ETH ETH…
Separate
Ethernet frames
Collective telegrams
(Real-time channel)
Collective telegrams
Communication cycle
Communication cycle
Communication cycle
Separate Ethernet
frames
t
t
t
RTi: Real-time data of node i, ETH: Ethernet frame with non-real-time data
…
…RT1
Padding
RT1 RT2 RT3 ETH1 ETH2 … RT1 …ETH1
RT1 RT2 … RT1 …RT3ETH1
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No. 8(c) SERCOS International 2009
Rx Rx
TxTx
Tx
Rx
Tx
Rx
Tx
Rx
Rx
Tx
Tx
Rx
Master Slave 1 Slave 2 Slave (n)
Direct cross communication in forward path
(here between slave 1 and slave 2)
Direct cross communication in reverse path
(here between slave 2 and slave 1)
CAT5
Real-time processing during passing through a node
Tx: Ethernet transmitter (Sender), Physical Interface
Rx: Ethernet receiver (Receiver), Physical Interface
Signal transmission without interpretation
Example: Cross Communication with SERCOS III
www.infoPLC.net
No. 9(c) SERCOS International 2009
Rx Rx
TxTx
Tx
Rx
Tx
Rx
Tx
Rx
Rx
Tx
Tx
Rx
Direct cross communication in forward path
(here between slave 1 and slave 2)
Indirect cross communication in reverse path (here between slave 2 and slave 1)
Rx Rx
TxTx
Tx
Rx
Tx
Rx
Tx
Rx
Rx
Tx
Tx
Rx
Master Slave 1 Slave 2 Slave (n)
Tx Rx Tx Rx
a)
b)
Tx Rx Tx Rx
CAT5
Real-time processing during passing through a node
Tx: Ethernet transmitter (Sender), Physical Interface
Rx: Ethernet receiver (Receiver), Physical Interface
Signal transmission without interpretation
Example: Cross Communication with EtherCAT
www.infoPLC.net
No. 10(c) SERCOS International 2009
Transmission of real-time data
in line topology
Detection of redundancy case
by redundancy manager (M)
Normal operation: Fault case:
Activation of reserve line
after successful reconfiguration
Fault case:
Example:Redundancy Concept of EtherCAT
M
S1
S2 S3
S4
t
M
S1
S2 S3
S4
M
S1
S2 S3
S4
Reserve line
(inactive during
normal operation
Link break during
reconfiguration
Activated
reserve line
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No. 11(c) SERCOS International 2009
Recovery time: < 25 µs
No reconfiguration required!
Cyclic, redundant transmission of
real-time data in primary and secondary ring
t
Splitting up into two lines
Normal operation: Fault case:
M
S1
S2 S3
S4
M
S1
S2 S3
S4
Example:Redundancy Concept of SERCOS III
www.infoPLC.net
No. 12(c) SERCOS International 2009
Example: Interoperability with SERCOS III and EtherCAT
SERCOS III
S-3 Profile
SERCOS III S-3 Profile
SERCOS III
S-3 Profile
SERCOS III
Ethercat
S-3-A
Ethercat DS402-B
Ethercat
DS402-C
Ethercat
…
Control
Vendor A
Vendor B
Vendor C
Control
Vendor A
Vendor B
Vendor C
Drives
Drives
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No. 13(c) SERCOS International 2009
Comparison of selected Real-Time Ethernet Solutions
SERCOS III EtherCATPROFINET
IRT
Ethernet
Powerlink
EtherNet/IP
+ CIPsync &
CIPmotion
Performance ++ ++ + o o
Ethernet
Conformity + o + ++ ++
Installed
Base + ++ + ++ o
Variety of
Suppliers &
Products+ ++ o o o
Indepen-
dence + o o o o
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No. 14(c) SERCOS International 20092007
Evolution of Fieldbus and Drivebus Technologies
DeviceNet
Profibus
Interbus
CANopen
SERCOS II
2001 2003 2005
Ethernet/IP+CIP Sync
Profinet IRT
Ethercat
Powerlink
SERCOS III
www.infoPLC.net
No. 15(c) SERCOS International 2009
Summary
SERCOS III …
combines the proven mechanisms of SERCOS interface (IEC
61491) with Ethernet (IEEE 802.3)
uses the established and proven synchronization mechanisms and
profiles of the existing SERCOS interface
allows an easy migration from SERCOS II to SERCOS III
is based on a cost-efficient and flexible standard hardware
covers all actual and future requirements for motion control
applications (C2C, Safety, I/O)
develops from a specialized drive bus to an universal real-time
Ethernet network
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